JP2006279581A - Projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projector capable of projecting a projection image in which trapezium distortion is corrected even if an operation such as image inversion is performed. <P>SOLUTION: An image processing system 57 consisting a projector 1 comprises a correction processing part for generating a trapezium correction image by executing a trapezium correction processing to a frame image stored in a buffer 56, and a inverted correction processing part for generating an inverted trapezium correction image by executing a inverted trapezium correction processing such that a short side of the trapezium correction image is replaced by a longer side thereof. A drive processing system 58 comprises an image information output part 582 for writing the inverted trapezium correction image in a liquid panel 251 based on a pixel driving signal for indicating the liquid panel 251 to drive, and an output switching part 581 for controlling the pixel driving signal when a reversing operation signal is input, and for causing the liquid panel 251 to write the inverted trapezium correction image which has been inverted in the liquid panel 251. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a projector.

  Conventionally, projectors have been used for presentations at conferences, academic conferences, exhibitions, and the like. Such a projector includes a light source, a light modulation device that modulates a light beam emitted from the light source, and a projection optical device that enlarges and projects the light beam modulated by the light modulation device on a screen.

When a projected image is formed on a screen using a projector, if the positional relationship between the projector and the screen is not appropriate, the projected image projected on the screen is, for example, a so-called trapezoid that is distorted into a trapezoid with a long upper side and a short lower side. Distortion may occur.
Therefore, a projector having a trapezoidal distortion correction function is known in which an optical image is distorted in advance and an appropriate rectangular projection image is formed when projected onto a screen (for example, Patent Documents). 1).

  The trapezoidal distortion correction function does not use all the pixels of the light modulation device, but distorts the image forming area in the light modulation device in a direction opposite to the distortion direction of the projection image on the screen, so that the projection image is rectangular. It corrects so that it may become a shape. According to the projector having such a trapezoidal distortion correction function, there is an advantage that a rectangular projection image can be projected even if the positional relationship between the projector and the screen is slightly shifted.

JP 2003-283963 A

By the way, when a presentation is performed using such a projector, the projected image may be inverted for visual effect, and this image inversion switches the order of data writing in the drive circuit that drives the light modulation device. This can be done by reversing.
However, as described above, when trapezoidal distortion correction is performed on the optical image, if the image order is reversed by simply reversing the writing order, the direction of the trapezoidal distortion correction is also reversed. On the other hand, a large trapezoidal distortion occurs. For this reason, in order to obtain a rectangular projection image, there is a problem that keystone distortion correction must be performed again.

  An object of the present invention is to provide a projector capable of projecting a projection image in which trapezoidal distortion is corrected even when an operation such as image inversion is performed.

  In order to achieve the above-described object, a projector according to the present invention includes a light source, a light modulation device that modulates a light beam emitted from the light source, a projection optical device that expands and projects the light beam modulated by the light modulation device, and A projector including a control unit that controls the entire apparatus including these, and an operation unit that outputs an operation signal corresponding to an applied operation to the control unit, wherein the control unit inputs image information A buffer for storing an image in units of frames formed by the image processing, an image processing system for performing image processing on the frame image stored in the buffer, and the light modulation based on the image information on which the image processing has been performed A drive processing system that performs drive control of the apparatus, and the image processing system is projected from the projection optical device on the frame image stored in the buffer When a correction processing unit that executes a trapezoidal correction process for correcting a trapezoidal distortion of a projected image to generate a corrected image and a reversal operation signal that instructs the reversal of the projected image are input from the operation unit, the correction is stored in the buffer. A reverse correction processing unit that performs reverse trapezoidal correction processing such that a short side and a long side of trapezoid correction of the correction processing image are switched with respect to the frame image that has been corrected, and generates a reverse correction processing image, The drive processing system includes an image information output unit that writes the reverse correction processed image generated by the reverse correction processing unit into the light modulation device based on a light modulation device drive signal instructing driving of the light modulation device; When the reversal operation signal is input from the operating means, the light modulation device driving signal is controlled to cause the image information output unit to write the reversed reverse correction processed image to the light modulation device. Characterized in that it comprises and.

  Here, the image information input to the projector is first stored in a buffer for each frame forming a frame image. Further, the image information stored in the buffer is subjected to image processing from the image processing system. The drive processing system outputs image information subjected to image processing to the light modulation device and drives the light modulation device based on the image information. The light beam emitted from the light source is modulated by the light modulation device, and a projection image is projected onto a screen or the like via the projection optical device.

  However, when the optical axis of the light beam projected from the projector is not perpendicular to the projection surface such as a screen, the projected image projected on the projection surface is, for example, a trapezoid whose upper side is deformed into a trapezoid longer than the lower side. Distortion occurs. In order to correct this trapezoidal distortion, in the present invention, the correction processing unit constituting the image processing system executes the keystone correction processing on the frame image formed by the image information stored in the buffer, thereby correcting the image. Is generated. The corrected image has a shape for correcting the distortion of the projected image, here, a trapezoid whose upper side is shorter than the lower side. When the drive processing system drives the light modulation device based on the correction processing image, a rectangular projection image in which the trapezoidal distortion is corrected is projected.

  Next, in order to invert the projection image in which the trapezoidal distortion is corrected in this way, the inverse correction processing unit constituting the image processing system stores the inversion operation signal output from the operation means in the buffer. A reverse correction process for generating a reverse correction process image is executed on the frame image formed by the image information. The generated reverse correction processing image has a trapezoidal shape in which the short side and the long side of the trapezoid correction of the correction processing image are interchanged, and here has an inverted trapezoidal shape in which the upper side is longer than the lower side.

Further, the image inversion unit constituting the drive processing system controls the light modulation device drive signal output from the image information output unit in accordance with the input inversion operation signal. The image information output unit writes the reverse correction processed image into the light modulation device based on the light modulation device drive signal controlled by the image inverting unit. Then, the reverse-corrected processed image is written in the light modulation device.
That is, the frame image formed on the light modulation device by the image information output unit is an inverted version of the reverse correction processed image, and has a trapezoidal shape whose upper side is shorter than the lower side. The light beam modulated by the frame image is inverted through a projection optical device, and a rectangular projection image in which trapezoidal distortion is corrected is projected.

That is, according to the projector of the present invention, it is possible to realize reverse projection of a projection image in which the trapezoidal distortion is corrected by a single trapezoidal correction process. Therefore, the projector of the present invention can easily project a projection image in which the trapezoid distortion is corrected without performing the trapezoid correction process again even if an operation such as image inversion is performed.
Further, the inversion of the projected image is achieved by the image inversion unit controlling the light modulation device drive signal and the image information output unit writing the image information to the light modulation device based on the light modulation device drive signal. Therefore, the amount of processing performed by the control unit of the projector can be suppressed.

  In the present invention, the reversal operation signal includes at least one of a vertical reversal operation signal for reversing the projection image in the vertical direction and a horizontal reversal operation signal for reversing the projection image in the left-right direction, and the image processing system includes It is preferable that a direction determination unit that determines whether or not the reverse direction indicated by the reverse operation signal and the trapezoidal distortion direction of the projection image are the same direction is provided.

  Here, in the case where the projection image subjected to the trapezoidal correction process is inverted with respect to the trapezoidal distortion in the vertical direction in which the lengths of the upper side and the lower side are different, when the projection image is inverted in the left-right direction, Since the correction direction of the trapezoid correction process is different, trapezoidal distortion does not appear in the inverted projected image. That is, when the trapezoidal distortion direction of the projection image and the inversion direction of the projection image are different, it is not necessary to perform the reverse trapezoid correction process on the image information.

  According to the present invention, when the up / down inversion operation signal or the left / right inversion operation signal is input, the direction determination unit determines whether the inversion direction specified by the inversion operation signal and the distortion direction of the projection image are the same direction. judge. Then, when it is determined that the reverse direction of the reverse operation signal and the distortion direction of the projection image are different directions, it is possible to cancel the inverted trapezoidal correction process performed on the input image information. That is, if the necessity of the inverted trapezoidal correction process is determined in advance and it is determined that there is no necessity, the execution of the process can be stopped. Therefore, the amount of processing performed by the projector can be suppressed.

  In the present invention, it is preferable that the image processing system includes an inverted trapezoidal correction process selection presentation unit that prompts the inverse correction processing unit to select the inverted trapezoidal correction process when the inversion operation signal is input.

  According to the present invention, as described above, when it is not necessary to execute the inverted trapezoidal correction process when the projected image is inverted, the inverted trapezoidal correction process selection presentation unit prompts the operator to select the inverted trapezoidal correction process. it can. That is, it can be left to the operator whether or not the reverse correction processing unit executes the reverse trapezoid correction process. Therefore, the amount of processing performed by the control means of the projector can be suppressed by the option that the operator does not execute the inverted trapezoidal correction processing.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to FIGS.
(1) Internal Configuration of Projector 1 FIG. 1 is a block diagram showing a schematic internal configuration of the projector 1 of the present embodiment.
The projector 1 modulates the light beam emitted from the light source in accordance with image information input to the projector 1 and projects the projection image A on the screen Sc. As shown in FIG. 1, the projector 1 includes an optical device 2, an operation panel 3 as an operation means, an imaging camera 4, and a control board 5 as a control means.

  Among these, the operation panel 3 is provided to be exposed on the outer surface of the projector 1 and is provided with a power switch, a distortion correction mode switch, a vertical reversing switch, a horizontal reversing switch, and the like. When each switch is operated, the operation panel 3 outputs an operation signal corresponding to each switch to the control board 5 described later.

For example, when a distortion correction mode switch is operated, the operation panel 3 outputs a distortion correction mode signal for executing trapezoid correction processing on input image information. When the up / down inversion switch is operated, the operation panel 3 outputs an up / down inversion signal instructing the upside down inversion of the projection image A. When the left / right reversing switch is operated, the operation panel 3 outputs a left / right reversing signal for instructing the reversal of the projected image A.
Note that the operation panel 3 and the switch may be provided in a remote controller (not shown) that performs remote control of the projector 1 using infrared rays.

  The imaging camera 4 includes an imaging device such as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS), and can capture the screen Sc and the projection image A. The imaging camera 4 outputs an imaging information signal based on the captured screen Sc and the projection image A to the control board 5 described later.

(1-1) Configuration of Optical Device 2 FIG. 2 is a schematic plan view showing an optical system of the optical device 2.
As shown in FIG. 2, the optical device 2 modulates the light beam emitted from the light source lamp 211 to form an optical image corresponding to image information input from the control board 5 described later, and the formed optical image. Is projected on the screen Sc (FIG. 1) by the projection lens.
Such an optical device 2 includes a light source device 21, an integrator illumination optical system 22, a color separation optical system 23, a relay optical system 24, an electro-optical device 25, a projection lens 26 as a projection optical device, and these Are housed in an optical component housing (not shown) and a head body (not shown) for holding and fixing the projection lens 26.

The light source device 21 includes a light source lamp 211 as a radiation light source, a reflector 212, and an explosion-proof glass 213. Then, the light source device 21 reflects the radial light beam emitted from the light source lamp 211 by the reflector 212 into a parallel light beam, and emits the parallel light beam to the outside through the explosion-proof glass 213.
Of these, the light source lamp 211 is a high-pressure mercury lamp in the present embodiment. In addition to a high-pressure mercury lamp, a metal halide lamp, a halogen lamp, or the like can be employed. Moreover, although the parabolic mirror is employ | adopted as the reflector 212, what combined the parallelizing concave lens and the ellipsoidal mirror instead of the parabolic mirror may be employ | adopted.

  The explosion-proof glass 213 is a light-transmitting glass member that closes the opening of the reflector 212. When the light source lamp 211 is ruptured, the fragments of the light source lamp 211 are not scattered outside.

  The integrator illumination optical system 22 is an optical system for substantially uniformly illuminating image forming areas of two liquid crystal panels 251 (to be described later) constituting the electro-optical device 25. The integrator illumination optical system 22 includes a first lens array 221, a second lens array 222, a polarization conversion element 223, and a superimposing lens 224.

The first lens array 221 has a configuration in which small lenses having a substantially rectangular outline when viewed from the optical axis direction are arranged in a matrix, and each small lens receives a plurality of light beams emitted from the light source device 21. It is divided into partial luminous fluxes.
The second lens array 222 has substantially the same configuration as the first lens array 221 and has a configuration in which small lenses are arranged in a matrix. The second lens array 222 has a function of forming, together with the superimposing lens 224, an image of each small lens of the first lens array 221 on a liquid crystal panel 251 described later.

  The polarization conversion element 223 is disposed between the second lens array 222 and the superimposing lens 224. Such a polarization conversion element 223 converts the light from the second lens array 222 into substantially one type of linearly polarized light, thereby improving the light use efficiency in the electro-optical device 25.

  Specifically, each partial light converted into substantially one type of linearly polarized light by the polarization conversion element 223 is finally substantially superimposed on a liquid crystal panel 251 (to be described later) of the electro-optical device 25 by the superimposing lens 224. Since only one type of linearly polarized light can be used in the projector 1 using the liquid crystal panel 251 of the type that modulates polarized light, almost half of the light from the light source lamp 211 that emits other types of randomly polarized light is not used. Therefore, by using the polarization conversion element 223, the light beam emitted from the light source lamp 211 is converted into substantially one type of linearly polarized light, and the light use efficiency in the electro-optical device 25 is enhanced.

  The color separation optical system 23 includes two dichroic mirrors 231 and 232 and a reflection mirror 233, and the dichroic mirrors 231 and 232 convert a plurality of partial light beams emitted from the integrator illumination optical system 22 into red (R), It has a function of separating light of two colors, green (G) and blue (B).

  The relay optical system 24 includes an incident side lens 241, a relay lens 242, and reflection mirrors 243 and 244, and red light, which is color light separated by the color separation optical system 23, is described later in the electro-optical device 25. The liquid crystal panel 251R has a function of leading to the liquid crystal panel 251R.

  At this time, the dichroic mirror 231 of the color separation optical system 23 transmits the red light component and the green light component of the light beam emitted from the integrator illumination optical system 22 and reflects the blue light component. The blue light reflected by the dichroic mirror 231 is reflected by the reflection mirror 233, passes through the field lens 255, and reaches a later-described blue light liquid crystal panel 251B of the electro-optical device 25. The field lens 255 converts each partial light beam emitted from the second lens array 222 into a light beam parallel to the central axis (principal light beam). The same applies to the field lens 255 provided on the light beam incident side of the other light modulators for green light and red light.

  Of the red light and green light transmitted through the dichroic mirror 231, the green light is reflected by the dichroic mirror 232, passes through the field lens 255, and reaches the liquid crystal panel 251G for green light. On the other hand, the red light passes through the dichroic mirror 232, passes through the relay optical system 24, further passes through the field lens 255, and reaches the liquid crystal panel 251R for red light.

The relay optical system 24 is used for red light because the optical path length of the red light is longer than the optical path lengths of the other color lights, thereby preventing a decrease in light utilization efficiency due to light divergence or the like. It is to do. That is, this is to transmit the partial light beam incident on the incident side lens 241 to the field lens 255 as it is. The relay optical system 24 is configured to pass red light out of the two color lights, but is not limited thereto, and may be configured to pass blue light and green light, for example.

The electro-optical device 25 modulates an incident light beam according to image information to form a color image. The electro-optical device 25 includes two incident-side polarizing plates 252 to which the respective color lights separated by the color separation optical system 23 are incident, and two liquid crystal panels 251 (red color) arranged on the downstream side of the respective incident-side polarizing plates 252. A liquid crystal panel for light 251R, a liquid crystal panel for green light 251G, and a liquid crystal panel for blue light 251B), and two exit-side polarizing plates 253 disposed in the latter stage of the optical path of each liquid crystal panel 251; And a cross dichroic prism 254 as a color synthesizing optical device. The liquid crystal panel 251 corresponds to the light modulation device of the present invention.
The incident side polarizing plate 252, the liquid crystal panel 251, the exit side polarizing plate 253, and the cross dichroic prism 254 are integrally unitized. The incident side polarizing plate 252, the liquid crystal panel 251, and the emission side polarizing plate 253 are arranged at predetermined intervals, although not specifically illustrated.

  The incident-side polarizing plate 252 receives light of each color whose polarization direction is aligned in approximately one direction by the polarization conversion element 223, and is substantially the same as the polarization axis of the light beam aligned by the polarization conversion element 223 among the incident light beams. Only polarized light in the direction is transmitted, and other light beams are absorbed. The incident-side polarizing plate 252 has a configuration in which a polarizing film is pasted on a translucent substrate such as sapphire glass or quartz.

The liquid crystal panel 251 has a configuration in which a liquid crystal that is an electro-optical material is hermetically sealed between a pair of transparent glass substrates. The liquid crystal panel 251 modulates the polarization direction of the polarized light beam emitted from the incident side polarizing plate 252 by controlling the alignment state of the liquid crystal in the image forming region in accordance with a drive signal output from a control board described later. To do.
The exit-side polarizing plate 253 has substantially the same configuration as the incident-side polarizing plate 252, and out of the light beams emitted from the image forming area of the liquid crystal panel 251, the polarization axis orthogonal to the light transmission axis of the incident-side polarizing plate 252. Only the light beam having a light is transmitted and other light beams are absorbed.

  The cross dichroic prism 254 is an optical element that synthesizes an optical image modulated for each color light emitted from the emission side polarizing plate 253 to form a color image. The cross dichroic prism 254 has a square shape in plan view in which four right-angle prisms are bonded together, and two dielectric multilayer films are formed on the interface where the right-angle prisms are bonded together. These dielectric multilayer films reflect each color light emitted from the liquid crystal panels 251R and 251B through the emission side polarizing plate 253, and transmit the color light emitted from the liquid crystal panel 251G through the emission side polarizing plate 253. In this way, the color lights modulated by the liquid crystal panels 251R, 251G, and 251B are combined to form a color image.

  The projection lens 26 has a configuration in which a plurality of lenses and a mirror that deflects an incident light beam are housed in a lens barrel, and enlarges a color image emitted from the electro-optical device 25 to display a screen Sc (FIG. 1). ). The projection lens 26 is disposed on the light beam exit side of the electro-optical device 25 and is fixed to a head body described later.

A predetermined illumination optical axis E is set inside the optical component casing, and the optical components 22 to 25 described above are arranged at predetermined positions with respect to the illumination optical axis E.
The head body is made of a metal material such as an aluminum alloy or a magnesium alloy, and integrates the electro-optical device 25 and the projection lens 26 and attaches the integrated unit to the optical component casing.

(1-2) Configuration of Control Board 5 The configuration of the control board 5 will be described with reference to FIGS.
The control board 5 corresponds to the control means of the present invention, processes image information input from the outside via the signal input terminal 11, and based on the image information and a control signal output from the CPU 51 described later. The drive control of the liquid crystal panel 251 is performed, and a predetermined optical image is formed on the liquid crystal panel 251. As shown in FIG. 1, the control board 5 includes a CPU (Central Processing Unit) 51, a ROM (Read Only Memory) 52, a RAM (Random Access Memory) 53, an imaging camera driver 54, a signal processing unit 55, The buffer 56, the image processing system 57, and the drive processing system 58 are generally configured.

The CPU 51 receives various signals output from the operation panel 3 and outputs a control signal for executing processing based on the signals. Further, the CPU 51 includes an imaging information analysis unit 511.
The imaging information analysis unit 511 analyzes the imaging information signal output from the imaging camera 4 and acquires the trapezoidal distortion amount and the trapezoidal distortion direction of the captured projection image A. Further, the imaging information analysis unit 511 outputs the acquired trapezoidal distortion amount and trapezoidal distortion direction to a trapezoid correcting unit 572 of the image processing system 57 described later.

The ROM 52 stores programs processed by the CPU 51 and various data.
The RAM 53 is used as a working memory for the CPU 51, and control data in the ROM 52 and the like are temporarily written as necessary.

The signal processing unit 55 performs signal processing such as analog / digital conversion and noise removal on the image information input via the signal input terminal 11. Then, the signal processing unit 55 outputs the image information after the signal processing to the buffer 56.
The buffer 56 is a memory for temporarily storing the image information output from the signal processing unit 55 as a frame image in units of frames. The buffer 56 outputs image information constituting the temporarily stored frame image to the image processing system 57.

(1-2-1) Configuration of Image Processing System 57 The image processing system 57 performs image processing on the image information output from the buffer 56 based on a control signal output from the CPU 51. The image processing system 57 includes image processing means 571 and trapezoidal correction means 572.
The image processing unit 571 adjusts the brightness, contrast, and the like according to the image adjustment signal output from the CPU 51 for the image information output from the buffer 56, and the brightness and color indicated by the image information. Execute gamma correction processing according to the degree.

FIG. 3 is a block diagram showing the configuration of the trapezoidal correction means 572.
The trapezoid correction unit 572 executes trapezoid correction processing for correcting the projection image A having trapezoid distortion into a rectangular shape for the image information output from the buffer 56. As shown in FIG. 3, the trapezoid correction unit 572 includes a correction data deriving unit 573, a correction processing unit 574, a direction determining unit 575, a reverse correction data deriving unit 576, and a reverse correction processing unit 577. .

  The correction data deriving unit 573 acquires the trapezoid distortion amount from the imaging information analysis unit 511, and derives correction data for correcting the trapezoid distortion of the projection image A based on the trapezoid distortion amount. Further, the correction data deriving unit 573 outputs the derived correction data to the correction processing unit 574.

The correction processing unit 574 performs trapezoidal correction processing on the image information output from the buffer 56 based on the correction data derived by the correction data deriving unit 573. Here, by the trapezoidal correction process executed by the correction processing unit 574, a frame image formed from the image information for one frame is generated as a trapezoidal corrected image transformed into a trapezoidal shape.
The correction processing unit 574 outputs the image information on which the trapezoid correction process has been performed to the drive processing system 58.

  When the inversion control signal is output from the CPU 51, the direction determination unit 575 acquires the trapezoid distortion direction from the imaging information analysis unit 511, and the inversion direction indicated by the trapezoid distortion direction of the projection image A and the inversion control signal. Are in the same direction.

  When the direction determination unit 575 determines that the trapezoidal distortion direction of the projection image A and the inversion direction of the inversion control signal are the same direction, the reverse correction data deriving unit 576 executes the correction processing unit 574. Correction data used in the trapezoidal correction process is obtained, and reverse correction data is derived based on the correction data. The reverse correction data is correction data for transforming the shape of the frame image formed by the image information into an inverted trapezoid shape in which the short side and the long side of the trapezoid correction image are exchanged.

The reverse correction processing unit 577 performs reverse trapezoidal correction processing on the image information output from the buffer 56 based on the reverse correction data derived by the reverse correction data deriving unit. Here, the frame image on which the inverted trapezoidal correction process has been performed is generated as an inverted trapezoidal corrected image having an inverted trapezoidal shape in which the short side and the long side of the trapezoidal corrected image are interchanged.
The reverse correction processing unit 577 outputs the image information on which the reverse trapezoid correction processing has been performed to the drive processing system 58.

  Here, the trapezoid correction processing performed by the correction processing unit 574 and the reverse trapezoid correction processing performed by the reverse correction processing unit 577 are, for example, changing the number of pixels in the scanning line of the frame image in units of a predetermined scanning line, or Digital processing that changes the number of scanning lines is performed.

(1-2-2) Configuration of Drive Processing System 58 The drive processing system 58 outputs image information input from the image processing system 57 to the liquid crystal panel 251 and performs drive control of the liquid crystal panel 251 based on the image information. . The drive processing system 58 includes an output switching unit 581 as an image inverting unit and an image information output unit 582.
First, the image information output unit 582 performs signal processing such as digital / analog conversion on the image information input from the image processing system 57. Image information is written into the liquid crystal panel 251 by driving each pixel of the liquid crystal panel 251 based on the image information. The driving of each pixel of the liquid crystal panel 251 is instructed by a pixel driving signal generated by the image information output unit 582 based on the image information. The image information output unit 582 outputs the image information after the signal processing and the generated pixel drive signal to the liquid crystal panel 251.
The output switching unit 581 controls the image information output unit 582 based on the inversion control signal output from the CPU 51. Specifically, the output switching unit 581 controls the pixel drive signal output from the image information output unit 582 based on the inversion direction indicated by the inversion control signal, and the image information output unit 582 writes image information. The process is switched as shown in FIG.

FIG. 4 is a schematic diagram illustrating a writing process in which the image information output unit 582 writes the image information C input from the image processing system 57 to the liquid crystal panel 251.
As shown in FIG. 4, the image information output unit 582 writes the image information C in the image forming area on the liquid crystal panel 251 and forms a frame image B on the liquid crystal panel 251.

  The output switching unit 581 does not switch the writing process of the image information output unit 582 when no inversion control signal is input. That is, as shown in FIG. 4A, the image information output unit 582 displays the image information C in the right-to-left writing direction and the top-to-bottom parallel order (image information C1, image information C2,. The image information C3... Is written on the liquid crystal panel 251 to form a frame image B.

When the up / down inversion control signal is input, the output switching unit 581 controls the pixel drive signal output from the image information output unit 582 and switches the writing process of the image information output unit 582 as follows. That is, as shown in FIG. 4B, the image information output unit 582 displays the image information C in the parallel order (image information C1, image information C2, image information from the right to the left output direction and from the bottom to the top). Information is written on the liquid crystal panel 251 in the order of information C3... To form a frame image B.
When the image information output unit 582 writes the image information C to the liquid crystal panel 251 in this way, a frame image B that is inverted upside down is formed on the liquid crystal panel 251.

Further, when the left / right inversion control signal is input, the output switching unit 581 controls the pixel driving signal output from the image information output unit 582 and switches the writing process of the image information output unit 582 as follows. That is, as shown in FIG. 4C, the image information output unit 582 displays the image information C in the parallel direction from the left to the right and from the top to the bottom (image information C1, image information C2, The image information C3... Is written on the liquid crystal panel 251 to form a frame image B.
When the image information output unit 582 writes the image information C to the liquid crystal panel 251 in this way, a frame image B that is horizontally reversed is formed on the liquid crystal panel 251.
Note that the reversal of writing can be realized by changing the output order of the image information, and can also be realized by changing the writing direction to the liquid crystal panel 251.

(2) Action of Control Board 5 FIG. 5 is a view showing the action executed by the control board 5, and FIGS. 6 to 9 are projected on the frame image formed by the image information in the projector 1 and the screen Sc. It is a schematic diagram which shows the projected image.
Here, an operation performed by the control board 5 in order to invert the projection image in which the trapezoidal distortion is corrected will be described with reference to FIGS.
The projector 1 is disposed at the lower center with respect to the surface of the screen Sc, and projects a projection image (FIG. 6B) on the screen Sc.

Here, the projector 1 inputs image information from the outside via the signal input terminal 11. The input image information is subjected to signal processing by the signal processing unit 55 and then temporarily stored in the buffer 56. The frame image B1 formed by the image information stored in the buffer 56 has a rectangular shape as shown in FIG.
The image information output from the buffer 56 is subjected to predetermined image processing by the image processing means 571 constituting the image processing system 57, and then output to the liquid crystal panel 251 by the drive processing system 58.

The liquid crystal panel 251 modulates the light flux based on the image information output from the drive processing system 58 to form an optical image. The formed optical image is enlarged and projected by the projection lens 26, and is projected as a projection image A1 (FIG. 6B) on the screen Sc.
In the projected image A1 projected at this time, a trapezoidal distortion in the vertical direction that is deformed into a trapezoid whose upper side is longer than the lower side appears.
Next, a case where the operator presses the distortion correction mode switch on the operation panel 3 in order to correct the trapezoidal distortion of the projection image A1 will be described.

The CPU 51 configuring the control board 5 monitors the input of the distortion correction mode signal output from the operation panel 3 (S1), and determines whether or not the distortion correction mode signal is input (S2). When the distortion correction mode signal is not input, the control board 5 returns to the process S1 and continues monitoring the distortion correction mode signal.
On the other hand, when the distortion correction mode signal is input, the CPU 51 outputs a control signal to the imaging camera driver 54. The imaging camera driver 54 drives the imaging camera 4 based on the control signal, and causes the imaging camera 4 to capture the screen Sc and the projection image A1 (FIG. 6B) (S3).

The imaging information analysis unit 511 configuring the CPU 51 analyzes the imaging of the screen Sc and the projection image A1 captured by the imaging camera 4 in the process S3, and acquires the trapezoidal distortion amount and the trapezoidal distortion direction of the projection image A1 (S4). . The imaging information analysis unit 511 outputs the acquired trapezoidal distortion amount and trapezoidal distortion direction to the trapezoidal correction unit 572 constituting the image processing system 57.
The correction data deriving unit 573 constituting the trapezoid correcting unit 572 derives correction data for the frame image B1 based on the trapezoidal distortion amount and the trapezoidal distortion direction acquired by the imaging information analyzing unit 511 in the process S4 (S5). The correction data deriving unit 573 outputs the derived correction data to the correction processing unit 574.

Based on the correction data received from the correction data deriving unit 573, the correction processing unit 574 performs trapezoid correction processing on the image information output from the buffer 56 (S6). Note that this image information has already been subjected to image processing by the image processing means 571.
As shown in FIG. 7A, the trapezoid correction image B2 formed by the image information subjected to the trapezoid correction processing has a shorter vertical length than the frame image B1 (FIG. 6A). The upper side is deformed into a trapezoid that is shorter than the lower side.
The correction processing unit 574 outputs the image information on which the trapezoid correction processing has been performed to the image information output unit 582 constituting the drive processing system 58.

  The image information output unit 582 outputs the image information received from the correction processing unit 574 and the pixel drive signal to the liquid crystal panel 251 and drives the liquid crystal panel 251 based on the pixel drive signal (S7).

The optical device 2 modulates the light beam emitted from the light source lamp 211 by the liquid crystal panel 251 and projects it onto the screen Sc. Then, the projection image A2 (FIG. 7B) with the trapezoidal distortion corrected is projected onto the screen Sc.
Next, when the operator presses the up / down inversion switch of the operation panel 3 to invert the projection image A2 (FIG. 7B) projected on the screen Sc in the up-down direction in order to obtain a visual effect. Is described.

  The CPU 51 monitors the input of the upside down operation signal output from the operation panel 3 (S8), and determines whether or not the upside down operation signal is input (S9). When the upside down operation signal is not input, the control board 5 ends the process.

On the other hand, when the upside down operation signal is input, the CPU 51 outputs the upside down control signal to the image processing system 57 and the drive processing system 58.
When the up / down inversion control signal is input from the CPU 51, the direction determination unit 575 constituting the image processing system 57 is acquired by the imaging information analysis unit 511 in the inversion direction (up / down direction) indicated by the up / down inversion control signal and processing S4. It is determined whether the trapezoidal distortion direction is the same direction (S10). When the direction determination unit 575 determines that the directions are not the same, the control board 5 ends the process.

  On the other hand, when the direction determination unit 575 determines that the directions are the same, the reverse correction data derivation unit 576 calls the correction data used in the trapezoid correction processing performed by the correction processing unit 574 in step S6 (S11), and Reverse correction data is derived based on the correction data (S12). The reverse correction data deriving unit 576 outputs the derived reverse correction data to the reverse correction processing unit 577.

Based on the reverse correction data received from the reverse correction data deriving unit 576, the reverse correction processing unit 577 performs reverse trapezoidal correction processing on the image information output from the buffer 56 (S13). Note that this image information has already been subjected to image processing by the image processing means 571.
As shown in FIG. 8, the inverted trapezoid corrected image B3 formed by the image information subjected to the inverted trapezoid correction process has a shorter vertical length than the frame image B1 (FIG. 6A), and the upper side. Is transformed into an inverted trapezoidal shape longer than the lower side.
The reverse correction processing unit 577 outputs the image information that has been subjected to the reverse trapezoidal correction processing to the image information output unit 582 that constitutes the drive processing system 58.

The output switching unit 581 constituting the drive processing system 58 controls the pixel drive signal output from the image information output unit 582 based on the upside down control signal input from the CPU 51, and performs the writing process of the image information output unit 582. Switching (S14). In the case of upside down, the writing process of the image information output unit 582 is switched to the writing process shown in FIG.
The image information output unit 582 outputs the image information received from the reverse correction processing unit 577 to the liquid crystal panel 251 together with the pixel drive signal (S15). As shown in FIG. 9A, the frame image B4 formed by the image information written on the liquid crystal panel 251 is obtained by inverting the inverted trapezoidal correction image B3 (FIG. 8) in the vertical direction. . The image information output unit 582 drives the liquid crystal panel 251 based on the output image information.

  The optical device 2 modulates the light beam emitted from the light source lamp 211 by the frame image B4 formed on the liquid crystal panel 251 and projects it onto the screen Sc. Then, a rectangular projection image A4 (FIG. 9B) obtained by inverting the projection image A2 (FIG. 7B) upside down is projected onto the screen Sc.

Here, referring to FIG. 10, the trapezoidal correction process, the inverted trapezoidal correction process, and the inverted output of the present embodiment described above are based on the processing process of the frame image obtained by performing these processes and the frame image. This will be described based on the deformation process of the projected image.
When projection is performed in the normal mode, trapezoid correction processing and upside down output are not performed on the image information input to the projector 1. Therefore, the image information forms a rectangular frame image B1. In the projection image A1 projected based on the frame image B1, a trapezoidal distortion in which the upper side is longer than the lower side appears.

  In order to correct the trapezoidal distortion of the projection image A1, a keystone correction process is performed on the image information input to the projector 1. Then, the image information after the keystone correction process forms a trapezoidal frame image whose upper side is shorter than the lower side, that is, a keystone correction image B2. The projection image A2 projected based on the trapezoid correction image B2 has a rectangular shape in which the trapezoidal distortion of the projection image A1 is corrected.

  In order to flip the projection image A2 upside down, a frame image B21 obtained by inverting the trapezoidal correction image B2 is formed on the liquid crystal panel 251 by the drive processing system 58. However, if the light flux is modulated and enlarged and projected based on the frame image B21, a larger trapezoidal distortion than the projection image A1 occurs in the projection image A21 projected on the screen Sc.

  In order to project a projection image in which the projection image A2 is turned upside down and the trapezoidal distortion is corrected, reverse correction processing is executed on the image information input to the projector 1. Then, the image information after the inverted trapezoidal correction process forms an inverted trapezoidal frame image whose upper side is longer than the lower side, that is, an inverted trapezoidal corrected image B3.

Next, the image information output unit 582 writes the inverted trapezoidal correction image B3 in the liquid crystal panel 251 based on the pixel drive signal controlled by the output switching unit 581. Then, a frame image B4 obtained by inverting the inverted trapezoidal correction image B3 is written on the liquid crystal panel 251.
The light beam modulated by the frame image B3 is inverted via the projection lens 26, and projects a rectangular projection image A4 in which trapezoidal distortion is corrected.

Thereby, according to the projector 1 of this embodiment, the reverse projection of the projection image A2 in which the trapezoid distortion is corrected can be realized by one trapezoid correction process. Therefore, the projector 1 according to the present embodiment can easily project the projection image A4 in which the keystone distortion is corrected without performing the keystone correction process again, even if an operation such as image inversion is performed.
The inversion of the projection image A2 is performed by the output switching unit 581 controlling the pixel driving signal, and the image information output unit 582 writing the inverted trapezoidal correction image B3 on the liquid crystal panel 251 based on the pixel driving signal. Since this is achieved, the amount of processing performed by the control board 5 of the projector 1 can be suppressed.

  In addition, when the up / down inversion operation signal or the left / right inversion operation signal is input from the operation panel 3, the direction determination unit 575 determines whether the inversion direction specified by the inversion operation signal and the distortion direction of the projection image are the same direction. Determine. Then, when it is determined that the reverse direction of the reverse operation signal and the distortion direction of the projection image are different directions, it is possible to cancel the inverted trapezoidal correction process performed on the input image information. That is, if the necessity of the inverted trapezoidal correction process is determined in advance and it is determined that there is no necessity, the execution of the process can be stopped. Therefore, the amount of processing performed by the control board 5 of the projector 1 can be suppressed.

  In the embodiment, the trapezoid correction process is automatically performed on the projection image A by the action of the control board 5 of the projector 1. However, the present invention may be configured such that the operator can correct the trapezoidal distortion of the projected image A by operating the distortion correction adjustment switch provided on the operation panel 3. As described above, when the trapezoid correction process is performed manually, it takes time for the operator. However, even if there is an operation such as image reversal, according to the present invention, the trapezoidal correction process is performed once, so that it is possible to reduce time and effort for the operator.

(3) Modification of the above embodiment The best configuration for carrying out the present invention has been disclosed in the above description, but the present invention is not limited to this. That is, since the embodiment does not limit the present invention, description of the names of members excluding some or all of the limitations on the shape, material, etc. is included in the present invention. is there.

For example, in the above-described embodiment, the process of reversing the projection image in which the trapezoidal distortion is corrected is taken up and down, but in the present invention, the process of reversing the projection image in the left-right direction can also be performed.
Further, the present invention can also be applied to a process of inverting a projection image D having a trapezoidal distortion in the vertical direction and the horizontal direction as shown in FIG.

  In the embodiment, the direction determination unit 575 determines whether or not the trapezoidal distortion direction of the projection image A and the reverse direction indicated by the reverse control signal are the same direction. When the reverse control signal is input, the inverted trapezoidal correction process selection presenting unit provided in the trapezoidal correction means 572 outputs a projection video asking whether or not to execute the reverse trapezoidal correction process to the projection image A to prompt the selection. Also good.

  According to such a configuration, when it is not necessary to execute the inverted trapezoidal correction process when the projected image is inverted, the inverted trapezoidal correction process selection presenting unit can prompt the operator to select the inverted trapezoidal correction process. That is, it can be left to the operator whether or not the reverse correction processing unit 577 performs the reverse trapezoidal correction process. Therefore, the amount of processing performed by the projector 1 can be suppressed when the operator takes the option of not performing the inverted trapezoidal correction processing.

In the embodiment, the screen Sc and the projection image A are captured by the imaging camera 4, and correction data for correcting the trapezoidal distortion is derived based on the imaging information. However, in the present invention, the projector 1 may include a tilt sensor that detects the tilt of the projector 1 with respect to the horizontal direction and the vertical direction, and the correction data may be derived based on the tilt data detected by the tilt sensor. .
In the above embodiment, the liquid crystal panel 251 is employed for the projector 1, but in the present invention, a digital micromirror device (registered trademark of Texas Instruments Inc.) may be employed.

  The present invention can be used for a projector having a trapezoidal correction processing function for a projected image.

1 is a block diagram showing an internal configuration of a projector according to an embodiment of the invention. The schematic plan view which shows the optical system of the optical apparatus concerning the said embodiment. The block diagram which shows the structure of the trapezoid correction | amendment means concerning the said embodiment. The schematic diagram for demonstrating the writing process of the image information output part concerning the said embodiment. The flowchart for demonstrating the effect | action of the control board concerning the said embodiment. The schematic diagram which shows the frame image concerning the said embodiment, and the projection image projected based on the said frame image. The schematic diagram which shows the trapezoid correction image concerning the said embodiment, and the projection image projected based on the said trapezoid correction image. The schematic diagram which shows the inverted trapezoid correction | amendment image concerning the said embodiment. FIG. 3 is a schematic diagram showing a frame image formed on the liquid crystal panel according to the embodiment and a projection image projected based on the frame image. The figure which shows the process of a frame image and a projection image concerning the said embodiment. The schematic diagram which shows the projection image projected on the screen concerning the modification of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Projector, 26 ... Projection lens (projection optical system), 211 ... Light source lamp (light source), 251, 251R, 251B, 251G ... Liquid crystal panel (light modulation device), 3 ... Operation panel (operation means), 5 ... Control Substrate (control means), 51 ... CPU, 511 ... imaging information analysis section, 55 ... signal processing section, 56 ... buffer, 57 ... image processing system, 572 ... trapezoid correction means, 573 ... correction data deriving section, 574 ... correction processing 575... Direction determining unit 576. Reverse correction data deriving unit 576. Reverse correction processing unit 58... Drive processing system 581... Output switching unit (image reversing unit) 582. , A2, A21, A4, D ... projected image, B, B1, B21, B4 ... frame image, B2 ... trapezoid corrected image, B3 ... inverted trapezoid corrected image

Claims (3)

A light source, a light modulation device that modulates the light beam emitted from the light source, a projection optical device that enlarges and projects the light beam modulated by the light modulation device, and a control unit that controls the entire device including them. Projector,
An operation means for outputting an operation signal corresponding to the given operation to the control means;
The control means includes a buffer that stores an image of a frame unit formed by input image information, an image processing system that performs image processing on the frame image stored in the buffer, and the image processing is executed. A drive processing system that performs drive control of the light modulation device based on the obtained image information,
The image processing system
A correction processing unit that generates a correction processing image by executing trapezoid correction processing for correcting trapezoidal distortion of the projection image projected from the projection optical device with respect to the frame image stored in the buffer;
When a reverse operation signal for instructing the reverse of the projection image is input from the operation means, the reverse is such that the short side and the long side of the trapezoid correction of the correction processing image are switched with respect to the frame image stored in the buffer. A reverse correction processing unit that performs trapezoidal correction processing and generates a reverse correction processing image,
The drive processing system is
An image information output unit for writing the reverse correction processed image generated by the reverse correction processing unit to the light modulation device based on a light modulation device drive signal instructing driving of the light modulation device;
When the inversion operation signal is input from the operation means, an image inversion unit that controls the light modulation device driving signal and causes the image information output unit to write the inverted reverse-correction processed image in the light modulation device. A projector characterized by comprising. The projector according to claim 1, wherein
The inversion operation signal includes at least one of an up / down inversion operation signal for inverting the projection image in the up / down direction and a left / right inversion operation signal for inverting the projection image in the left / right direction,
The image processing system includes a direction determination unit that determines whether or not the reverse direction indicated by the reverse operation signal and the trapezoidal distortion direction of the projection image are the same direction. . In the projector according to claim 1 or 2,
The image processing system
A projector comprising: an inverted trapezoidal correction process selection presentation unit that prompts selection of the inverted trapezoidal correction process by the inverse correction processing unit when the reverse operation signal is input.

Images